A number of companies have started marketing LED lamps that can be switched to a red mode. The claim is that red light is less harmful to one's night vision. Given that our eyes are less sensitive to ...

I've noticed that when I'm out at night stars seem to vanish when I focus on them. I assume the reason is physiological and not astronomic. Why does this happen? I would expect that things would be ...

If you are in pitch black and you close your eyes, you sometimes can see strange shapes of various colors. A lot of the time these shapes and colors change as you observe them. This phenomenon still ...

The electroretinogram (ERG) is generally considered to reflect the retinal processing of a light stimulus, typically a photoreceptor response followed by secondary neuronal activity.
I am wondering ...

Today I wondered what the first organism to evolve vision would have been. I assume that it would have been kind of primitive and basic, but of course extremely innovative and eventually useful to a ...

My ten year old son was reading car number plates that were too fast, too far away and at the wrong angle for any of us to read or even believe that it was possible for him to read. We thought he was ...

It is fairly common knowledge that the lens in its normal state absorbs ultraviolet (UV) radiation. An interesting notion has come up from time to time in my reading that suggests there are a small ...

I often read that people believe that human vision has an inherent frames-per-second rate (FPS) that causes stroboscopic effects - such as seeing the spokes of a rotating wheel apparently rotating at ...

As far as I am aware, the saccades of the eye are central to visual perception. If the eye is held still, the human stops seeing, even if light is reaching the retina and the visual pathway is intact. ...

I've been to local zoo the other day and one lizard caught my attention: its pupils are circular, which, I thought, is not usual for reptiles. Turns out it is, but now I can't find any explanation on ...

When a person is spying from around a corner with only one eye, it's rather easy to ignore the other eye's image, since it's probably much darker, because one usually spies around a corner standing ...

I was trying to do some stimulation for SSVEPs by strobing a solid black square and a solid white square. Weird thing was, I ended up seeing weird grid like patterns that looked like this, always of ...

I was asking myself this weird question.
When you get up or stand up too fast, sometimes, you see something like a dark veil, and you aren't able to see anything distinctly for 2 or 3 seconds, then ...

I have noticed when in a dark room light and color seem to be brighter and more intense in the corner of my eyes. For example the light that comes from my digital clock seems like a dark pink when I ...

Photosensitive epilepsies are characterized by visually-induced seizures. Flashing-light stimuli are known to induce seizures in some (but not all) patients. My question is whether people with this ...

So, I am not sure I can reproduce it via images, but the steps are:
1) At night, open a window and have a look at the surface of the earth
2) Suppose there's an object that reflects a tiny amount of ...

In a vacuum, there is a one-to-one correspondence between light frequency ($\nu$) and wavelength ($\lambda$), ie. $\lambda=c/\nu$. But in a refractive medium, $\lambda=v/\nu$, so while the frequency ...

I want to design a project for EEG signal processing. In my research I found the concept of SSVEP. SSVEPs represent the electrical activity of the brain as measured via EEG, and are evoked by visual ...